it. these are more placards. explosives, anything orange, reds yellow. oxidizer, that's going to make a small fire into a really big fire without much help. inhalation hazards, don't breathe it. okay. the rest it self explanatory. there is nfpa 704 diamonds, you don't need to know that blue, health. :number 4 it will wreck your health fast. 0 means no problem. red, same. 4 means it's a fire hazard and poof, catch on fire like that.